Study On The Biomimetic Synthesis Of Hydroxyapatite In The Presence Of Polysaccharides

Hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂, HA or HAP] can be widely used as the substitution of bone transplantation, and is a significant bio-medicine material. In recent years, biomimetic synthesis has been widely used in biomedical materials preparation. To get the HA with the function fully in line with people's needs, the most promising method to synthesize the artificial bone-like synthetical materials is biomimetic. The essence of the biomimetic process lies in mimicking the biomineralization, in which an organic phase provides a template for inorganic crystals to nucleate and grow from supersaturated solution. This paper, based on the principles of biomineralisation, the different shaped HA were synthesised through the biomimetic method with polysaccharides as templates.This study takes Ca(NO₃)-2·4H₂O and (NH₄)₃PO₄·3H₂O as reagents. Spindle shaped hydroxyapatites (HA) 30-40 nm in length and 7-8 nm in width, were synthesised with 0.5%CS as template in 6% (v/v) hydrogen peroxide solution for 7 days by biomineralization. With ChS or Pu as templates, by controlling the concentration of the organics we successfully synthesized the flake 100 nm in length and 30 nm in width and silk shaped HA by biomineralization. The flake-shaped HA was also synthesized in agarose gel, the effect of the gel concentration on the the crystal size was studied.The crystal phase of obtained samples was characterized by X-ray powder diffraction (XRD) analysis, Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Thermogravimetric analyzers-microcomputer differential thermal analyzers (TG-DTA) and Electrical conductivity (EC). It is indicated that the interaction between the HA and polysaccharides may be one of the reasons which influence the nucleation and growth of HA.